Conveyor chain assembly

Abstract: A conveyor chain assembly (10) including a multiplicity of rows of chain modules (12), each module includes a plurality of link ends (24) with coaxially aligned openings (30). A chain pin (46) passes through the coaxially aligned openings of adjacent modules. On the opposite ends of each module is a plug socket (54) which is adapted to house a plug (80). The plug includes a shaft (82) and an arm (96). The arm is moveable when the shaft is mounted in the socket between a first position in which the arm restricts axial movement of the chain pin and a second position in which the arm does not restrict axial movement of the chain pin.

Description: This invention relates to a modular conveyor chain assembly of the type as defined in the preamble of claim 1, a plug for use with that chain assembly, and a module for use in that chain assembly. Some prior art conveyor chains are comprised of rows of molded plastic chain modules pivotally joined together by chain pins. Each module of such chains has a plurality of spaced lid ends which intermesh with the complementary lid ends projecting from a module in an adjacent row. Further, each link end has therein a bore which is coaxially aligned with the bores of other link ends to house the chain pin. In some arrangements, the chain pin projects from each edge or side of the conveyor chain and is provided with a head on one end of the chain pin to restrict axial movement of the chain pin. The head can be preformed but, in most cases, the head is formed by heat and pressure after the chain pin has been placed in position in the module. The head also projects from the side of the conveyor and can catch or drag on adjacent structures thus requiring additional lateral clearance between the conveyor and the conveyor guide or between adjacent conveyor chains. To remove the chain pin from an assembled chain, the head on one end of the chain pin has to be cut off. Once the head is severed, the chain pin becomes unusable because its length is too short to form a new head. Prior art conveyor chains of the type as described in the preamble of claim 1 include plugs housed in the opposite ends of the link end bores to restrict axial movement of the chain pins (EP-A-288 409, EP-A-459 691 or EP-A-503 333). The plugs of such chains are normally small parts that can be lost or dropped on the floor of a production facility when they are inserted or removed from the modules. In some prior art constructions, these plugs have a tendency to be dislodged or pop out of the module when the conveyor chain is in use. Without the plug restricting axial movement of chain pin, the chain pins can become dislodged from their proper position and cause a disruption in the conveyor assembly. The invention as claimed in claim 1 provides a conveyor chain assembly including a multiplicity of rows of chain modules. Each module includes an intermediate section, a plurality of link ends projecting forwardly and rearwardly from the intermediate section with respect to the direction of movement of the conveyor chain. The link ends of each chain module intermesh with the link ends of the chain module in the adjacent row. A chain pin passes through aligned bores provided in the intermeshing link ends between the rows. The module at each end of the row of modules includes a plug socket which houses a plug. The plug includes a first portion mounted in the socket and a second portion which is pivotable when the first portion is mounted in the socket. The second portion is pivotable between a first position in which the second portion restricts axial movement of the chain pin and a second position in which the second portion does not restrict axial movement of the chain pin. One object of the invention is to provide a conveyor chain assembly in which the chain pin can be accessed or removed from the module without damaging the chain pin and without damaging or removing the plug. The plug remains in the module after initial insertion so that the plug cannot be lost or dropped. The plug is pivotable in the module with a hand tool between a position which restricts axial movement of the chain pin and a position which does not restrict axial movement of the chain pin. A further object of the invention is that the plug is securable in the module in two separate locations which reduces the possibility the plug will pop out of the module. A further object of the invention is that the axial forces on the chain pin cause the chain pin to engage the plug in such a manner as to secure the plug in the module even more thus reducing the possibility the plug will pop out of the module. The plug also distributes the axial forces on the chain pin to the module. The plug can thus operate under greater adversities while providing a greater level of reliability to the user. Fig. 1 is a top plan view of a conveyor chain assembly according to the invention. Fig. 2 is a bottom plan view of the conveyor chain assembly shown in Fig. 1. Fig. 3 is an enlarged end view of a portion of the conveyor chain assembly shown in Fig. 1 and including an end of a chain module with an arm of a plug in a chain pin blocking position. Fig. 4 is a view taken along line 4-4 in Fig. 3 and with portions broken away for purposes of illustration. Fig. 5 is a view similar to Fig. 3 showing the arm of the plug in a first position. Fig. 6 is a partial side view taken along line 6-6 in Fig. 3. Fig. 7 is a view taken along line 7-7 in Fig. 5 and with portions broken away for purposes of illustration. Fig. 8 is a perspective view of the plug. Referring to the drawings describing a preferred embodiment of the present invention, a conveyor chain assembly 10 is illustrated in Figs. 1 and 2 and includes a multiplicity of rows of intermeshed chain modules 12 of which only three are depicted in Figs. 1 and 2. While in the illustrated construction the rows of modules are made up of only a single module, the rows of modules could include more than one module to form a wider conveyor chain. Each module 12 may be comprised of molded plastic and includes opposite ends 16 and 18, an intermediate section 20 and a longitudinal axis 22. A plurality of link ends 24 project forwardly and rearwardly from the intermediate section 20 with respect to the direction of movement of the conveyor chain 10. A first set 26 of link ends 24 projects forwardly of the intermediate section 20 and a second set 28 of link ends 24 projects rearwardly of the intermediate section 20. The intermediate section 20 thus integrally joins the first set 26 and the second set 28 of link ends 24. The link ends 24 include therethrough coaxially aligned openings or bores 30. Either the first set 26 or the second set 28 of link ends 24 includes a special type of link end or terminating link end 32 which forms each end 16 and 18 of the module 12. The terminating link end 32 includes an outer portion 34, an inner portion 36 and an end wall 38 (Figs. 3 and 5). The coaxially aligned opening 30 of the terminating link end 32 has an outer part 40 and an inner part 42. The outer part is defined by an annular wall 44 (Figs. 4 and 7). The link ends 24 of each module 12 intermesh with the link ends 24 of a module 12 in an adjacent row to form the conveyor chain. The modules 12 are interconnected in this intermeshed position by a pivot, hinge or chain pin 46 running through the coaxially aligned openings 30 of the intermeshed link ends 24 of adjacent modules 12. The chain pin 46 has a longitudinal axis 48 (Fig. 4) and two ends 50, 52. Continuing to refer to Figs. 1 and 2, the module 12 further includes a socket 54 on each end 16 and 18 of the module 12. More specifically, the socket 54 is defined by the intermediate section 20 and the terminating link end 32. The socket 54 includes a shaft cavity 56 that is parallel to the direction of the coaxially aligned openings 30 and parallel to the axis 22 of the module 12. The shaft cavity 56 has a longitudinal axis 58 and is spaced from the coaxially aligned openings 30. The shaft cavity 56 includes a first inlet 60, a second inlet 62 (Fig. 4), a head portion 64, and a leg portion 66. A wall 68 separates the head portion 64 from the leg portion 66. The wall 68 has an outer and an inner surface 70 and 72 respectively and has an aperture 74 therethrough. The aperture 74 allows communication between the head portion 64 and the leg portions 66. The socket 54 further includes an arm cavity 76 having an inlet 78 (Fig. 4). The arm cavity 76 is transverse to the direction of the coaxially aligned openings 30 and transverse to the axis 22 of the module 12. The arm cavity 76 communicates with the shaft cavity 56. The arm cavity 76 separates the terminating link end 32 into the outer portion 34 with the outer part 40 of the opening 30 and the inner portion 36 with the inner part 42 of the opening 30. The arm cavity 76 communicates with both the outer and inner parts 40 and 42 of the opening 30. As shown in Figs. 4 and 8, a chain pin retaining plug 80 is mountable in the module 12 for selectively restricting axial movement of the chain pin 46. The plug 80 includes a first portion or shaft 82 that is mountable in the shaft cavity 56 of the socket 54. The shaft 82 includes a shank 84 with a circular head 86 extending therefrom. The head 86 has a top surface 88 having therein a slot 90. The shaft 82 further includes means for securing the plug 80 in the socket 54 in the form of a pair of spaced legs 92 extending from the shank 84 in a direction opposite to that of the head 86. The legs are resilient such that the legs 92 can be deflected. Each leg 92 is tapered to facilitate insertion into the module 12 and each leg 92 terminates in a shoulder 94. Continuing to refer to Figs. 4 and 8, the plug 80 further includes a second portion or arm 96 that is selectively housed in the arm cavity 76 of the socket 54 and moveable between a first position wherein the arm 96 does not restrict axial movement of the chain pin 46 (Fig. 5) and a second position wherein the arm 96 does restrict axial movement of the chain pin 46 (Fig. 4). The arm 96 is integral with and extends outwardly from the shank 84. A projection 98 extends from the arm 96 in the same direction the head 86 extends from shank 84. As shown in Fig. 8, the projection 98 has a top surface 100, a pair of linear edges 102 and 104 and a pair of curved edges 106 and 108. The top surface 100 has a pair of chamfered portions 110 and 112 that are adjacent the curved edges 106 and 108 and a rectangular portion 114 between the chamfered portions 110 and 112. The projection 98 comprises a means for releasably positioning the arm 96 in the arm cavity 76. The plug 80 is insertable into the module 12 as follows with reference to Figs. 4, 5, and 7. With resilient legs 92 first, the shaft 82 is moved in the shaft cavity 56 via the first inlet 60 in a direction parallel to the axis 48 of the chain pin 46. As the plug 80 is moved further into the shaft cavity 56, the resilient legs 92 contact the outer surface 70 of the wall 68 and must deform inwardly to enable the shoulders 94 to slide through the aperture 74. After the shoulders 94 have passed through the aperture 74 and into the leg portion 66 of the shaft cavity 56, the legs 92 resume their original orientation and spring outwardly. In this position, the shoulders 94 contact the inner surface 72 of the wall 68 and the wall 68 does not allow the shoulders 92 to pass back through the aperture 74 thus retaining the plug 80 in the socket 54 and providing a snap-fit. This first snap-fit is intended to be permanent in that the plug 80 is not designed to be removed from the module 12 after placing it in this position. Further, in this position, the head 86 is flush with the end 16 of the module 12, and the shank 84 contacts the outer surface 70 of the wall 68 to prohibit the plug 80 from moving further into the interior of the module 12. As shown in phantom in Fig. 5, the arm 96 is in its first position filling the second inlet 62 of the shaft cavity 56 and not restricting the axial movement of the chain pin 46 such that the chain pin 46 can be inserted or removed from the aligned opening 30 in the link ends 24 without interference from the plug 80. When axial movement of the chain pin 46 needs to be restricted, such as when the conveyor is in operation, the arm 96 is moved into the second position as follows. Referring to Fig. 5, a tool such as a slotted screw driver is inserted into the slot 90 of the head 86 and rotated to enable the plug 80 to be pivoted about the axis 58 of the shaft cavity 56. The plug 80 is rotatable in only one direction because the end wall 38 of the terminating link end 32 prohibits rotation of the plug 80 in the other direction. While the plug 80 is being pivoted in the socket 54, the arm 96 enters the arm cavity 76 through the inlet 78 and the rectangular portion 114 of the top surface 100 of the projection 98 contacts the outer portion 34 of the terminating link end 32 causing the outer portion 34 to deform outwardly. This outward deformation allows the arm 96 to pass further into the arm cavity 76 until the projection 98 is clear of the outer portion 34 and the outer portion 34 returns to its normal orientation thus providing a second snap-fit as shown in Fig. 4. In this second position as shown in Figs. 3, 4, and 6, the arm 96 is fully inserted into the arm cavity 76 with no part thereof projecting outwardly from the module 12. The arm 96 occludes communication between the outer and inner parts 40 and 42 of the opening 30. Further, the projection 98 extends into the outer part 40 of the opening 30 such that the curved edges 106 and 108 of the projection 98 contact the annular wall 44 and restrict pivotal movement of the arm 96 out of the arm cavity 76. In this second position, the arm 96 restricts axial movement of one end 50 of the chain pin 46. As shown in Figs. 1 and 2, a second plug 80 in this position on the other end 18 of the module 12 would restrict axial movement of the other end 52 of the chain pin 46. If the rows of the conveyor chain assembly include more than one module 12, a plug 80 is inserted only into the socket of the modules 12 that form the ends of the rows. Thus, only two plugs 80 are utilized per row for either row configuration. The second snap-fit is not intended to be permanent in that it is disengagable. If access or removal of the chain pin 46 is desired, the plug 80 is not removed from the module 12 but rather pivoted so that the arm 96 returns to the first position as hereafter described. The slotted screw driver is placed into the slot 90 of the head 86 and rotated to pivot the plug 80. As the plug 80 is pivoted, the chamfered portion 112 of the projection 98 causes the outer portion 34 to deform outwardly enabling the arm 96 to clear the outer portion 34 of the terminating link end 32 and return to the first position in which the plug 80 does not restrict the axial movement of the chain pin 46. Once the plug 80 is inserted into and secured in the shaft cavity 56, it is not designed to be removable from the module 12. However, even though the plug 80 is not removable from the module 12, the chain pin 46 can still be removed or alternatively its movement restricted. The invention allows access to each chain pin 46 from either end of the row via the plug 80. When the plug 80 is restricting axial movement of the chain pin 46, the plug 80 is more securely positioned in the module 12 because of the two snap-fits which reduce the chances of the plug 80 popping out of the module 12. More specifically, the arm 96 provides additional load carrying capacity to the plug 80. In the ideal operation of the conveyor chain assembly 10, the arm 96 is not required to assume much load. However, when a product is channeled to one side of the conveyor chain assembly 10 or the conveyor chain assembly 10 is misaligned, an uneven load distribution in the link ends 24 results. This uneven load can be transmitted to the chain pin 46 causing an axial component of the uneven load to force the chain pin 46 out to one side of the module 12. Because the arm 96 is perpendicular to the axis 48 of the chain pin 46, these axial forces of the chain pin 46 cause the pin to engage the arm 96 in such a manner as to lock the plug 80, and more specifically the projection 98 of the arm 96, in place all the more as well as distribute the axial load of the chain pin 46 onto the terminating link ends 32. This transfer of forces causes the plug 80 to work under greater adversities while providing a greater level of reliability to the user. Further, the plug 80 does not project outwardly of the module 12 because the arm 96 is in the arm cavity 76 and the head 86 is flush with the end 16 of the module 12. This positioning of the plug 80 does not alter the top of the conveyor chain assembly 10 and allows independent conveyor chains to run next to each other at equal or different speeds without the need for guides and without the fear of jamming. Running multiple conveyor chains very close together provides improved product handling and transfer of products on and off the conveyor chains.

Claims: A modular conveyor chain assembly comprising a multiplicity of chain modules (12) arranged in rows having lateral ends (32), said module (12) including a plurality of link ends (24) projecting outwardly from said module (12), the link ends (24) of the module (12) in one row intermeshing with the link ends (24) of the module (12) in an adjacent row, at least some of said link ends including coaxially aligned openings (30) adapted to receive a chain pin (46) having a longitudinal axis (48), said module (12) at each lateral end (32) of said row of modules (12) including a socket (54), and a plug (80) being mountable in said socket (54) for restricting axial movement of said chain pin (46); characterized in that said plug (80) when mounted in said socket (54) is supported for pivotal movement between a first position not restricting axial movement of the chain pin (46) and a second position restricting axial movement of the chain pin (46). A chain assembly as set forth in claim 1, wherein said plug (80) includes a first portion (82) mounted in said socket (54) and a second portion (96) which is moveable by said first portion (82) between said first and second positions when said first portion (82) is housed in said socket (54). A chain assembly as set forth in claim 2, further characterized in that said first portion (82) pivots in said socket (54) about an axis parallel with respect to the longitudinal axis (48) of the chain pin (46). A chain assembly as set forth in claim 2 or 3, further characterized in that said first portion includes a shaft (82) and said second portion includes an arm (96) projecting outwardly from said shaft (82) and wherein said arm (96) occludes one of said coaxially aligned openings (30) in said link ends (24) when said arm (96) is in its second position. A chain assembly as set forth in claim 4, further characterized in that said socket (54) includes a shaft cavity (56) adapted to house said shaft (82), and an arm cavity (76) adapted to house said arm (96) when said arm is in its second position. A chain assembly as set forth in claim 5, further characterized in that said shaft cavity (56) is spaced from said coaxially aligned openings (30). A chain assembly as set forth in claim 5 or 6, further characterized in that said module (12) has a longitudinal axis (22), and wherein said shaft cavity (56) is parallel with respect to said longitudinal axis (22) of said module (12), and said arm cavity (76) is transverse with respect to said longitudinal axis (22) of said module (12). A chain assembly as set forth in any one of claims 1 to 7, further characterized by means (92,94) for securing said plug (80) in said socket (54). A chain assembly as set forth in claim 8, further characterized in that said securing means includes at least one resilient leg (92) on said plug (80). A chain assembly as set forth in any one of claims 4 to 7, further characterized in that said shaft (82) has opposite ends, one of said opposite ends includes at least one resilient leg (92) and the other of said opposite ends includes a head (86). A chain assembly as set forth in claim 10, further characterized in that said head (86) is positioned in said socket (54) such that said head (86) is flush with one of the opposite ends (16,18) of said module (12). A chain assembly as set forth in any of claims 5 to 11, further characterized by means (98) for releasably positioning said arm (96) in said arm cavity (76). A chain assembly as set forth in claim 12, further characterized in that said positioning means includes a projection (98) on said arm (96). A chain assembly as set forth in any of claims 1 to 13, further characterized in that said plurality of link ends (24) includes a first set of link ends (26) having said coaxially aligned openings (30) and projecting forwardly of said module (12) and a second set of link ends (28) having said coaxially aligned openings (30) and projecting rearwardly of said module (12) with respect to the direction of movement of the conveyor chain (10). A chain assembly as set forth in claim 10, further characterized in that said module (12) has an end surface and wherein said plug (80) is mounted in said socket (54) such that said head (86) is flush with said end surface. A chain assembly of any one of claims 1 to 15, wherein said row is formed by a single module (12) having opposite ends (16,18) each provided with said socket (54) for receiving said plug (80). A plug (80) for use with the chain assembly of any one of claims 1 to 16, characterized by a first portion including a shaft (82) having a longitudinal pivot axis (58), the first portion being insertable into the socket (54) in the direction of the longitudinal axis; and a second portion (96) integral with the said first portion (82) and projecting from the first portion in a direction transverse to the longitudinal pivot axis (58), said second portion (86) being positioned when said plug (80) is in its first position to permit axial movement of the chain pin (46) and positioned when said plug (80) is in its second position to restrict axial movement of the chain pin (46). A plug as set forth in claim 17, wherein said second portion comprises an arm (96) projecting outwardly from said shaft (82). A plug as set forth in any one of claims 17 or 18, further including means (92,94) for securing said plug (80) in the socket (54). A plug as set forth in claim 19 wherein said securing means includes at least one resilient leg (92) on said first portion (82). A plug as set forth in any one of claims 17 to 20 wherein said plug (80) further includes means (98) for removably positioning said second portion (96) in said second position. A module for forming the modular chain assembly of any one of claims 1 to 16, comprising a lateral terminating link end (32), said terminating link end (32) including said socket (54) adapted to pivotally receive said plug (80).

Inventors: SCHLADWEILER TIMOTHY J, SCHLADWEILER, TIMOTHY J.
Applicants: REXNORD CORP, REXNORD CORPORATION
Application year: 1994
Main classification: B65G17
IPC codes: B65G17, B65G47